The present invention relates to smoke and fire detection devices in alarm systems, and in particular to low cost devices which are in wireless communication with a central control unit and can detect temperature conditions that are out of range for both hot and cold extremes.
Modern fire detectors include both smoke detection methods and heat detection circuitry, for example ADEMCO's 5808 detector includes a photoelectric smoke detector and a thermistor which is set to trip if the temperature rises above 135 degrees Fahrenheit. The thermistor is necessary for fires which may not generate smoke quickly enough for the alarm to be raised by the smoke detection circuitry alone.
In addition there are low temperature or freeze detectors available, such as ADEMDO's 5816temp, which are commonly installed in uninhabited vacation homes in order to raise an alarm if a freezing pipe situation could possibly occur. Since the alarm system in these homes most likely contains fire detectors, it would be convenient and less costly to use a common thermistor circuit to sense both high and low temperature.
Although U.S. Pat. No. 5,764,143 teaches the use of a thermistor (already in the alarm system for temperature compensation of a PIR sensor) for sensing high and low temperature conditions, it does not teach the use of a thermistor located in a wireless smoke detector. Since a wireless smoke detector transmits data via RF communication, it needs to comply with the control/data restrictions imposed by the FCC. A wireless smoke detector also uses a battery for power; giving rise to the need for battery conservation techniques.
It is therefore an object of the present invention to provide a wireless integrated smoke detector and temperature monitoring device which detects fire and high and low temperature trouble conditions.
It is a further object of the present inventing to provide a wireless integrated smoke detector and temperature monitoring device which conserves battery power to ensure good battery life.
It is yet a further object of the present invention to provide a wireless integrated smoke detector and temperature monitoring device which complies with transmission data restrictions imposed by the FCC.